Ultrafast Surface Photochemistry in the VUV

This project was part of a TMR Network. Being part of a TMR network is often hard work, including walking up snowy mountain roads and skiing. During this work, we built a rather unique machine to study ultrafast (about 1 ps or less) photochemistry in the vacuum ultraviolet regime. A schematic drawing of the apparatus appears below. The required photons were made through a laser-based technique: high harmonic generation with an Ar-ion-pumped Ti:sapphire laser. This laser produces roughly 80 fs pulses at a wavelength near 800 nm. The output of the Ti:sapphire laser is focused into a rare gas that flows out of a tube in a vacuum chamber, as shown in the photo on the right. A nonlinear interaction between the laser field and the atoms in the rare gas jet creates the photons that we are after: ~10-40 eV or 120-30 nm. We studied the photochemistry of  O2 adsorbed on graphite. This was the first use of HHG to initiate surface photochemistry.

Diagram of single shot autocorrelator
Diagram of single shot autocorrelator

For further information on related topics, try these sites:

  • Kapteyn-Murnane Labs
  • Attosecond physics in Lund
  • Attosecond and High Field Physics at the MPI Garching (These guys do incredible work but this is the worst website ever. To be fair, I'm sure it's a work in progress.)
  • High Harmonic Generation
  • Movies of HHG
  • More on HHG
  • Labs working in Surface Science, Nanotechnology and Catalysis
  • Dynamics of Gas-Surface Interactions
Back to top of page.